The most common reason for plugins not being loaded is that something is wrong with required libraries. You can not mix debug and release libraries. If you do, plugins using them will fail to load.

On Mac the port qt4-mac by default only builds release. To build both, you can do:

sudo port upgrade --enforce-variants qt4-mac +debug +quartz

Under mac os the default mouse settings only include one mouse button which is used by OpenFlipper to apply rotations. 

To get all functions, go to your systems mouse settings and set the right click as secondary button and the middle button to button 3.

Qt is compatible with Visual Studio 2010. Therefore you can use Visual Studio 2010 to compile OpenFlipper with Qt version 4.8 or greater.

OpenFlipper and especially Qt below it, may not work correctly when debug and release versions of the libraries get mixed. For example using release version of qwt but debug version of OpenFlipper while usually cause plugins to fail at startup or crash while the program is running.